They are ideal for smooth non-porous surfaces like Glass, Plastic, Metal, Mirrors, Whiteboards, Chalkboard Stickers, Tiles, Message Boards, LED Writing Boards, Window, Ceramic, Menu Boards, Vinyl, Granite etc.
Chalk Paint and Chalkboards are produced by a wide variety of manufacturers. Therefore, it is necessary to check if it is porous or non-porous. We advise that it is best to test in a small area before using on any surface. Porous surfaces can absorb the ink and would tend to leave some trace on the surface when wiped. Having said that many customers use Ninja Chalk markers to create permanent designs!
You can seal a porous surface (like some painted Chalkboards) so that you can easily wipe off your liquid chalk markers or you can also seal on top of your chalk markers designs so they can't be erased. We recommend using an Acrylic Sealer or Acrylic Spray, follow the manufacturer's instructions for number of coats and other steps. Always test a small area before using it.